Loudspeaker and like instrument



Feb. 23, 1937. R. R. GLEN LOUDSPEAKER AND LIKE INSTRUMENT Filed March 27, 1935 Patented Feb. 23, 1937 LOUDSPEAKER AND LIKE INSTRUMENT Robert Rodger Glen, Anglet, France, assignor to Glen's Patents and Holdings, Inc., New York, N. Y., a corporation of Delaware Application March 27, 1935, Serial No. 13,241

This invention relates to improvements in loudspeakers and like instruments and has for its object generally to provide means whereby the tone quality of the instrument may be corrected or improved or may be altered as desired to suit special conditions.

More specifically, it is an object of the invention to provide readily applied means for modifying the tone quality of a loudspeaker or like instrument in the form of an adhesive damping or loading agent associated with the diaphragm. Such agent may conveniently comprise a coating on the diaphragm of the instrument, at selected points or zones distributed over its surface, of 16 adhesive non-resonating material.

diaphragm is intended to include any sound emitting member whether it is of plane, conical or other form.

Other objects of the invention will in part be 20 obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts, which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawing, in

which:

Fig. 1 is a view in vertical section, taken on the line l-I in Fig. 2, showing a loudspeaker of the electro-dynamic type, constructed in accordance with the invention; and

Fig. 2 is a front elevational view of the loudspeaker shown in Fig. 1.

Referring now to the drawing, an electrodynamic loudspeaker is illustrated having a main sound cone or diaphragm 5 mounted to be actuated by suitable driving means such as the spaced driving diaphragm 6, provided as set forth in my copending application, Serial No. 748,474, filed October 16, 1934. The loading agent is shown as applied in two zones to the main sound cone as bands, at Ill and 20, which encircle the cone.

In applying the invention to a loudspeaker of the electro-dynamic type employing a cone, the loading agent is preferably applied to the outer In Great Britain July 4, 1934 2 Claims. (Cl. 181-31) surface of the cone, as shown, in one or more bands disposed substantially in a corresponding number of planes that are normal to the axis of the cone.

By non-resonating material is meant material which is inelastic compared with the material of the cone and as an example of such material it has been found that a mixture of pumice and fish-glue with a suitable binder, such as bitumen, is suitable. The material may be applied while hot with a brush and the bands are preferably as thick as possible normal to the surface of the cone and of any desired width, for example, inch. By suitably disposing the bands of nonresonating material on the outer surface of the cone the tone qualities of the cone and consequently of the instrument of which it forms a part, may be varied within wide limits and the distribution of the bands may be selected (by trial and error) to give any special or desired effect.

Since certain changes may be made in the above construction and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In loudspeakers and like instruments, the combination with electrodynamic driving means, of a conical sound emitting diaphragm in operative association with said driving means, and a loading agent disposed on said diaphragm and having boundaries defined by the intersection of planes with the cone that are substantially normal to the axis of the cone; said agent consisting of one or more continuous flexible bands of non-resonant material.

2. In loudspeakers and like instruments, the combination of the character set forth in claim 1, in which the loading agent is adhesively applied and has greater average density than the diaphragm and has a composition consisting of a mixture of pumice, fish-glue and bitumen.

The term ROBERT R. GLEN. 

